From 140de383d9d26e8be300b7ba86d56b47898cd8c9 Mon Sep 17 00:00:00 2001
From: Joakim Zhang <qiangqing.zhang@nxp.com>
Date: Tue, 30 Jul 2019 18:01:11 +0800
Subject: [PATCH] can: flexcan: add CAN wakeup function for i.MX8

The System Controller Firmware (SCFW) is a low-level system function
which runs on a dedicated Cortex-M core to provide power, clock, and
resource management. It exists on some i.MX8 processors. e.g. i.MX8QM
(QM, QP), and i.MX8QX (QXP, DX).

SCU driver manages the IPC interface between host CPU and the
SCU firmware running on M4.

For i.MX8, stop mode request is controlled by System Controller Unit(SCU)
firmware.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
 drivers/net/can/flexcan.c | 99 ++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 13 deletions(-)

--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -29,6 +29,11 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/regmap.h>
 
+#ifdef CONFIG_IMX_SCU_SOC
+#include <linux/firmware/imx/sci.h>
+#include <dt-bindings/firmware/imx/rsrc.h>
+#endif
+
 #define DRV_NAME			"flexcan"
 
 /* 8 for RX fifo and 2 error handling */
@@ -223,6 +228,7 @@
 #define FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN	BIT(7) /* default to BE register access */
 #define FLEXCAN_QUIRK_SETUP_STOP_MODE		BIT(8) /* Setup stop mode to support wakeup */
 #define FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD	BIT(9) /* Use timestamp then support can fd mode */
+#define FLEXCAN_QUIRK_USE_SCFW			BIT(10) /* Use System Controller Firmware */
 
 /* Structure of the message buffer */
 struct flexcan_mb {
@@ -323,6 +329,11 @@ struct flexcan_priv {
 	struct regulator *reg_xceiver;
 	struct flexcan_stop_mode stm;
 
+#ifdef CONFIG_IMX_SCU_SOC
+	/* IPC handle when enable stop mode by System Controller firmware(scfw) */
+	struct imx_sc_ipc *sc_ipc_handle;
+#endif
+
 	/* Read and Write APIs */
 	u32 (*read)(void __iomem *addr);
 	void (*write)(u32 val, void __iomem *addr);
@@ -352,7 +363,8 @@ static const struct flexcan_devtype_data
 static struct flexcan_devtype_data fsl_imx8qm_devtype_data = {
 	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
 		FLEXCAN_QUIRK_USE_OFF_TIMESTAMP | FLEXCAN_QUIRK_BROKEN_PERR_STATE |
-		FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD,
+		FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD | FLEXCAN_QUIRK_SETUP_STOP_MODE |
+		FLEXCAN_QUIRK_USE_SCFW,
 };
 
 static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
@@ -503,6 +515,32 @@ static void flexcan_enable_wakeup_irq(st
 	priv->write(reg_mcr, &regs->mcr);
 }
 
+#ifdef CONFIG_IMX_SCU_SOC
+static void flexcan_stop_mode_enable_scfw(struct flexcan_priv *priv, bool enabled)
+{
+	struct device_node *np = priv->dev->of_node;
+	u32 rsrc_id, val;
+	int idx;
+
+	idx = of_alias_get_id(np, "can");
+	if (idx == 0)
+		rsrc_id = IMX_SC_R_CAN_0;
+	else if (idx == 1)
+		rsrc_id = IMX_SC_R_CAN_1;
+	else
+		rsrc_id = IMX_SC_R_CAN_2;
+
+	val = enabled ? 1 : 0;
+	/* stop mode request */
+	imx_sc_misc_set_control(priv->sc_ipc_handle, rsrc_id, IMX_SC_C_IPG_STOP, val);
+}
+#else
+static int flexcan_stop_mode_enable_scfw(struct flexcan_priv *priv, bool enabled)
+{
+	return 0;
+}
+#endif
+
 static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
 {
 	struct flexcan_regs __iomem *regs = priv->regs;
@@ -512,9 +550,12 @@ static inline int flexcan_enter_stop_mod
 	reg_mcr |= FLEXCAN_MCR_SLF_WAK;
 	priv->write(reg_mcr, &regs->mcr);
 
-	/* enable stop request */
-	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
-			   1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
+	 /* enable stop request */
+	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_SCFW)
+		flexcan_stop_mode_enable_scfw(priv, true);
+	else
+		regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
+				   1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
 
 	return flexcan_low_power_enter_ack(priv);
 }
@@ -525,8 +566,11 @@ static inline int flexcan_exit_stop_mode
 	u32 reg_mcr;
 
 	/* remove stop request */
-	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
-			   1 << priv->stm.req_bit, 0);
+	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_SCFW)
+		flexcan_stop_mode_enable_scfw(priv, false);
+	else
+		regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
+				   1 << priv->stm.req_bit, 0);
 
 
 	reg_mcr = priv->read(&regs->mcr);
@@ -1782,11 +1826,6 @@ static int flexcan_setup_stop_mode(struc
 		gpr_np->full_name, priv->stm.req_gpr, priv->stm.req_bit,
 		priv->stm.ack_gpr, priv->stm.ack_bit);
 
-	device_set_wakeup_capable(&pdev->dev, true);
-
-	if (of_property_read_bool(np, "wakeup-source"))
-		device_set_wakeup_enable(&pdev->dev, true);
-
 	return 0;
 
 out_put_node:
@@ -1794,6 +1833,30 @@ out_put_node:
 	return ret;
 }
 
+#ifdef CONFIG_IMX_SCU_SOC
+static int flexcan_setup_stop_mode_scfw(struct platform_device *pdev)
+{
+	struct net_device *dev = platform_get_drvdata(pdev);
+	struct flexcan_priv *priv;
+	int ret;
+
+	priv = netdev_priv(dev);
+
+	ret = imx_scu_get_handle(&(priv->sc_ipc_handle));
+	if (ret < 0) {
+		dev_err(&pdev->dev, "get ipc handle used by SCU failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+#else
+static int flexcan_setup_stop_mode_scfw(struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
 static const struct of_device_id flexcan_of_match[] = {
 	{ .compatible = "fsl,imx8qm-flexcan", .data = &fsl_imx8qm_devtype_data, },
 	{ .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
@@ -1936,9 +1999,19 @@ static int flexcan_probe(struct platform
 	devm_can_led_init(dev);
 
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE) {
-		err = flexcan_setup_stop_mode(pdev);
-		if (err)
+		if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_SCFW)
+			err = flexcan_setup_stop_mode_scfw(pdev);
+		else
+			err = flexcan_setup_stop_mode(pdev);
+
+		if (err) {
 			dev_dbg(&pdev->dev, "failed to setup stop-mode\n");
+		} else {
+			device_set_wakeup_capable(&pdev->dev, true);
+
+			if (of_property_read_bool(pdev->dev.of_node, "wakeup-source"))
+				device_set_wakeup_enable(&pdev->dev, true);
+		}
 	}
 
 	return 0;